The Compact All-in-One AMI MUSIK DDH-1 Audio Music Interface
The AMI MUSIK DDH-1 ($549)
These days, many of us use computers as transport. No more fiddling with optical mediajust call up a big list of albums in your media player software of choice. It's great to be presented with multiple terabytes worth of music, to be combed through by artist or genre or year, or just browse by album cover. It brings the simplicity of an iPod type experience to the home, with a much larger display and without any sonic compromise.
I mention compromise because there's usually something. For those with massive budgets and unlimited space, it's not hard to find DAC and amp separates that do the job well. Maybe even add in a preamp for your speaker rigwhy not? You've got no shortage of cash or room. For others though, it's not always so easy. Many folks use their desktop as a sort of catch all music spacethe headphone listening takes place there, and throw some active monitors in the mix as well. Most desktop situations don't allow unlimited space for big separates, so we enter the realm of the all in one DAC/amp/preamp unit.
There seems to be no shortage of these types lately. Some of them are really quite good too. But if you're really strapped for space, many of these are just too bulky, and lot of them start at $1,000 and go up from there. Size can be a factor, and you'd be surprised at how many of these leave out some important features. Under review today is one that doesn't lack much at allthe AMI Musik DDH-1.
Design and Features
Hailing from Tokyo Japan, AMI (short for Audio. Music. Interface. Seriously, that's how they write it with the periods) is an up and coming firm with a lot of new models on the drawing board. The DDH-1 ($549) is their first releasea compact, full featured unit with more functionality than you can shake a stick at, including some you maybe didn't even know you needed. This thing is seriously small at 4.5 inches wide, under 6 inches deep, and less than 2 inches in height, and should fit into even the most crowded desktop environment. Allow me to break down the features since there's a lot to cover.
First up is the DAC section. The DDH-1 is centered around the 32-bit Texas Instruments PCM1795 DAC. It features an XMOS-based asynchronous USB input capable of handling 24-bit/192kHz data. Interestingly, AMI chose to use a newer USB 3.0 type B port. It's not a true USB 3.0 input, mind you, but AMI figured they would physically accommodate the newer style cables as those will become more and more common. Of course, it still works with USB 2.0 cables if that's what you have, it's just not quite as robust of a connection. Also worth noting is compatibility with the iPad via the Camera Connection Kit which is not something you find in a lot of 24/192 capable devices. Toslink and coaxial SPDIF ports, which I suppose by now are considered "legacy" formats, are on board as well.
What's that I see? A 1/8" analog input? Surely that's just used in a pinch to feed music from a cell phone or something, right? True, that input does route sound to the line out or headphone amp sections, but there's more to it than that. It actually runs the signal through an AKM AK5386 analog to digital converter, which results in a 24-bit/96kHz digital signal accessible through the Toslink output. So this little device could be used to digitize analog recordings from whatever source you might have. Ever want to mess with needle drops of your favorite vinyl albums? The DDH-1 can do that. Or maybe you have a collection of cassette tapes from local bands which will never in a million years be released on any other format. The DDH-1 can archive those too, and from my testing it does a great job of it. This function does require a sound card with an optical input capable of accepting 96kHz signals, which most decent soundcards can do by now (though integrated sound solutions in motherboards seem to have moved on to HDMI). It would be nice to have the option of capturing incoming analog signals directly through USB, but I can only think of one similar device (Alpha Design Labs GT40) that works that way.
Let's see... what else to mention? The Toslink output will pass through information from the USB input, meaning the device can act as a dedicated (and rather high quality) USB to SPDIF converter. A rear panel switch sets the output to either fixed or variable, so those not using the volume control for preamp duties can get that unnecessary stuff out of the signal paththough in my experience it seems pretty transparent. Up front, AMI had the foresight to add headphone jacks in both 1/4" and 1/8" varieties. I suppose it's no big deal to slap on an adapter, but somehow it just feels "right" to use a dedicated jack in the proper size. As if that wasn't enough, the unit has dedicated sample rate indicators to help keep track of incoming signals. I really can't think of another all-in-one cramming anywhere near this much into such a small box.
I have to say I like the attitude displayed by AMIthey come right out and list the specific components used in the DDH-1. Go HERE and scroll down a bit, then choose "components" and you'll see exactly what the guts of the device are made of. This means I spend less time describing all this stuff in my review, but more importantly it shows a certain confidence in their choiceslike they have nothing to hide. Noteworthy items, aside from those previously mentioned, include the TI DIX9211 (a new and very high quality digital audio receiver), a TPA 6120A2 headphone driver, low jitter TCXO system clock, and Nichicon Fine Gold capacitors. Power supply is a larger external unit much like you'd find with a small laptop computer. AMI uses a DC to DC converter to generate the supply voltage, so this is a more complex solution than the simple wall-wart as commonly found in this size/price segment.
AMI uses quad opamps to form the analog output stage: a National LM49860 stereo opamp handles I/V conversion, and another of the same chip handles low-pass filtering. Then dual NJM2114D bipolar opamps are used as a buffer, feeding the line out as well as the headphone driver. All opamps are socketed to encourage swappingthough the stock opamps are of rather high quality, AMI wanted to allow for experimentation or to achieve different flavors of sound. I tried a few different opamps I had lying around and found myself going right back to the originals for the best balance and overall character. But I'm glad the option is there, and maybe one day I'll find something that does offer a substantial improvement.